How to calculate the quantification of qPCR to the equivalent of the number of nuclei in fungi? I have a question about the quantification through qPCR. The my question is: if I made the qPCR of a fungal functional gene, how is possible to obtain from the quantification number (in nanogram) the equivalent number in number of nuclei?

From your comment:

> "As few as 148 fg of Verticillium dahliae DNA were detected and quantified (through qPCR), which is equivalent to five nuclei". How is possible to make this convertion?

The _Verticillium dahliae_ JR2 genome is 36.2 Mb. Assuming this organism is haploid and dsDNA has an average mass of 660 g/mol per base pair, that means the molar mass of the genome is 2.40 × 1010 g/mol. Therefore, 5 nuclei will contain 8.30 × 10-24 mol of your genome. Multiplying the molar mass by the number of moles gives us a mass of 1.99 × 10-13 g, or 199 fg, which is close to your cited value.